Underwater dual tubing well completion



June15,1965 I J. A. HAEBER 3,189,097

UNDERWATER DUAL TUBING WELL COMPLETION Filed April 27. 1961 5 Sheets-$heet 1 FIG. 3

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FIG. 1

lNVENTOR J. A. HAEBER BY: Hm

IS AGENT FIG. 4-

June 15, 1965 J. A. HAEBER umamwmmz mm, 'rusme WELL COMPLETION Filed April 27. 1961 7 5 Sheets-Sheet 2 \NVENTOR J. A. HAEBER HIS AGENT FIG.7

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June 15 1965 J. A. HAEBER 3,189,097

UNDERWATER DUAL TUBING WELL COMPLETION Filed April 27. 'l9 6l 5 Sheets-Sheet 4 INVENTOR:

' a. A. HAEBER BY: g m

ms AGENT June 15; 1965 J. A. HAEBER 3,189,097

I UNDERWATER DUAL TUBING WELL COMPLETION Filed April 27'. 1961 5 sheets-sheet s FIG. l2

lNVENTOR J. A. HAEBER QHHTM HlS AGENT United States Patent ,1 7 UNDERWATER DUAL TUBING WELL COMPLETION Y- John A. Haeber, Houston, Tex.,-assignori to Shell Oil Company, New York, N.Y., a corporation of Delaware Filed Apr. 27, 1961, Ser. No. 105,968 8 Claims. (Cl. 166--66.5)

This invention relates to drilling .of .offshore wells and pertains more particularly to a method and apparatus for completing wells drilled in offshore Waters which may be anywhere from 100 to 1500 or more feet deep. The present invention is especially concerned with a method and apparatus for suspending, packing off, and locking down dual tubing strings in a casing and tubing suspension body or casinghead positioned under water.

For purposes of illustration the present invention will be described with regard to a method and apparatusdrilled atan offshore locationwherein the well casinghead is' located below thesurface of the water.

A further object of the present invention is to provide a method and apparatus .for maintaining control of the pressure within the well throughout the time needed to install production tubing strings therein from a remote location above the surface of the water.

Another object of the present invention is to provide a method and apparatus for installing, from a remote location above the surface of the water, a tubing string within a well having a well casinghead positioned below the surface of the water in a manner such that the complete pressure control of the well is maintained at all times while emergency auxiliary pressure control of thewell is also available substantially throughout the entire operation of installing the tubing string.

In the drilling and completion of an oil well at an offshore location in a manner described in copending patent application, Serial No. 830,538, filed July 30, 1959, and entitled Underwater Well Completion Method, wherein the well casinghead is located on the ocean floor, it would be extremely difficult and take considerable time to run one or more tubing strings down through open water to the casinghead. It is therefore desirable to have guide means extending from the top of the casinghead to the operational platform above the surface of a body of water. Therefore, it is preferred that the tubing string or strings be run through a marine conductor pipe string into the well to a predetermined depth, say 10,000 feet. In the event that multiple strings are being run into the well, considerably more time is taken in this operation is generally the tubing strings must be run one at a time because of the difiiculties encountered in running them together. It is therefore another object of the present invention to provide a marine conductor pipe string in communication with and secured to a casinghead during the running of tubing strings therein and later removed from the casinghead prior to attaching the wellhead assembly thereto.

These and other objects of this invention'will be understood from the following description taken with reference to the drawing, wherein:

FIGURES 1-4 are schematic views showing the instalfurther into the well.

3,189,097 Patented June 15, 1965 'ice lation of dual tubing strings into an casinghead; Y

, FIGURES 5-7 are schematic views showing the lower- Eig of a wellhead assembly on an underwater well casingead;

FIGURE 8 is a longitudinal view of a.tubing adapter for installing dual tubing strings in an'underwater well;

FIGURE 9 is a longitudinal view taken in cross-section of the lower end of a wellhead assembly connected to dual tubing strings;

FIGURES 10 and 10A are diagrammatic views illustrating two possible arrangements for packers and tubing within a well;

FIGURE 11 is a plan view of the tubing lock-down assembly of FIGURE 9; and,

FIGURE 12 is a view taken in partial longitudinal cross-section of a hydraulically-actuated running and re underwater well trieving tool.

Referring to FIGURE 1 of the drawing, an underwater well which has been drilled in any suitable manner, such for example, as by the method described in copending patent application, Serial No. 830,538, filed July 30, 1959, and entitled Underwater Well Completion, wherein a well casinghead or a casing and tubing suspension body 11 is positioned on the ocean floor, the top of the casinghead 11 being closable during drilling and completion operations by one or more blow-out preventers 13 and 14. A marine conductor pipe string 15 is secured to the top of the uppermost blow-out preventer 14 and extends upwardly through the water to an operational base above the surface of the water such as the deck of a drilling barge 16.

As illustrated in FIGURE 1, the well is ready to have one or more strings of tubing run down into the well through the equipment on the casinghead which comprises the marine conductor 15 and the blow-out preventers 13 and 14 which are locked securely together in a fluidtight manner and also locked to the casing and tubing suspension body or casinghead 11 in a manner shown in copending patent application, Serial No. 830,538, filed July 30, 1959.

In some circumstances, for example, on development wells drilled in areas where well pressures are known to be low, tubing, may be run into place within the well casing with blow'out preventers 13 and 14 omitted and the marine conductor 15 connected directly to the casinghead 11. However, it is preferred that blow-out preventers be employed.

If a single string of tubing is to be run into the well, it is provided with a temporary or permanent tubing hanger or any suitable stop member at its upper end by which the tubing string is otherwise prevented from dropping Preferably, the well is provided with a pair of tubing strings so that tools, instruments, or other devices may be circulated down throughv the tubing to the bottom of the well and returned by reverse circulation. Parallel as well as concentric tubing strings'may be installed in the manner according to the present invention.

Tubing strings 22 and 26 are shown in FIGURE 8 as being fixedly secured at its upper end to atubing hanger 23 or other suitable stop member which in turn is temporarily secured in any suitable manner to a tubing adapter 24 and. run into the well as shown in FIGURE 1. The tubing adapter 24 (FIGURE 8) is provided with a fishing neck 25.

The tubing adapter 24 is shown in FIGURE 8 as being secured by means of a split ring connector 31 to a tubing hanger 23. The split ring connector 31 may be secured by screws 33 or other suitable means. In FIGURE 12 the adapter 24 is shown as being provided with a large nut 29 for connecting it to the tubing hanger 23. The upper end of the tubing string 22 is preferably connected to a slope-shouldered donut hanger 34 to hold it down in place as the tubing is run into the well. The fishing neck at the upper end of the tubing adapter 24 is adapted to engage a running and retrieving tool 30 secured to the lower end of a running pipe string 17 (FIGURE 1).

Prior to running the tubing strings 22 and 26 into the well, a Baker Oil Tool, Inc., Model 415 DB wireline-set single bore production packer 37 is installed in the inner casing string 18 (FIGURE to close it above the single production interval to control the well pressure after removal'of the blow-out preventers 13 and 14 (FIGURE 1) and prior to setting the wellhead assembly. Alternatively, instead of employing a packer 37 in which the lower end of tubing string 22 is slidably seated, the well casing 18 may be closed to formation fluids under pressure by filling the casing with a fluid such as water or drilling mud.

Additionally, a Brown Oil Tool Company dual bore hydraulically-set packer 38 may be fixedly secured to the tubing strings 22 and 26 and run into the well. The wireline-set packer 37 in the bottom of the casing 18 is provided with a wireline retrievable plug 39 in a manner well known in the art, which plug is subsequently removed after the wellhead assembly is installed. The lower packer 37 and its plug 39 provide a temporary closure means for containing the well pressure during completion of the well, while the dual production packer 38 prevents casing pressures and corrosive fluids from going up the well during the production thereof. Alternatively, the two tubing strings 22 and 26;are connected together in fluid communication at a point 90 above'the' packer 37 with a common tubing section 91 being inserted in packer 37.

In a preferred embodiment of the present invention, the lower portion of the tubing string below the dual packer 38 is perforated to permit circulation of a fluid down one tubing 22 and up the other tubing 26 at a point, above closed packer 37.

In FIGURE 1 of the drawing, the upper end of tubing strings 22 and 26, with the tubing hanger 23 and adapter 24 connected thereto, are shown as being lowered through conductor pipe by a running string 17 and running head by which they are run into position within the casinghead 11. In FIGURES 2 and 8, the tubing strings 22 and 26 are shown as being seated in the tubing hanger 23 with adapter 24, it being understood that at the time this operation is carried out the tubing hanger 23 is seated on the hanging shoulder 40 of the innermost casing string 18, as shown in FIGURE 8.

With the tubing strings 22 and 26 installed within the well and the running string 17 withdrawn therefrom, as shown in FIGURE 2, the marine conductor pipe 15 and its landing head are disconnected from the blow-out preventers 13 and 14 and Withdrawn upwardly to the drilling barge16. A running string 17 is then run down to unlock the blow-out preventers 13 and 14 in a manner described in copending application, Serial No. 830,538, filed July 30, 1959, after which the disconnected blowout preventers are raised together with their associated equipment to the drilling barge 16 as illustrated in FIG- URE 3. In some wellhead arrangements, the blow-out preventers may be raised to the surface along with the marine conductor if hydraulically-operated means are used to lock the preventers to the casinghead. f

A running string 17 (FIGURE 4) having the running and retrieving tool 30 (FIGURE 12) attached to the lower end thereof is guided to the casinghead in a manner described in copending application, Serial No. 830,538, filed July 30, 1959, and run into the casing and tubing suspension body or casinghead 11 to engage the tubing adapter 24. By means of the running string 17 the tubing adapter 24, together with the two tubing strings 22 and 4 26 connected thereto, are withdrawn upwardly from the landing position on the shoulder 40 (FIGURE 8) of the casing hanger 41 and pulled upwardly (FIGURE 4) to the barge 16 where the tubing hanger 23 is disconnected from the tubing adapter 24.

The tubing adapter 24 (FIGURE 8) is removed by unscrewing the set screws 33 of the split ring connector 31 and substituting for adapter 24 the lower end of a tubing hanger lock-down device 50, which is in turn secured by a flange at the top of member to the bottom'of a wellhead assembly or production control unit 49 (FIGURE 5). The tubing hanger lock-down body 50 isprovided with a pair of vertical conduits 51 and 52 arranged to register with the tubing strings 22 and 26. Prior to connecting the split ring conector 31 to the tubing hanger lock-down body 50, sealing subs 56 and 57 are positioned above the collars 36 and 55, The sealing ring 58 is positioned between elements 23 and 50. Primary packing O-ring seals 60 and 61 contain the annulus pressure between the tubing string or strings and the production casing 18 while a seal 62 is provided in the sloping face of the top of the lock-down body 50 to keep sea water out of the installation. As illustrated, the weight of the tubing strings 22 and 26 is supported with the sloping face 63 of the hold-down body 50 hearing against the mating face on the upper end of the tubing and easing suspension body or casinghead ll. However, if desired, a portion or all of the weight may be put on shoulder 40 by having tubing hanger 23 rest thereon.

The lock-down body 50 (FIGURE 9) is provided with a series of hydraulically and radially-slidable locking dogs 64 adapted to move outwardly from the body 50 and seat in the annular groove 42 of the casing and tubing suspension body 11. A piston 65 is adapted to move vertically under fluid pressure from conduit 66, forcing the dogs 64 outwardly to lock in the annular groove 42. When fluid pressure is applied through conduit 67 to move the piston in the opposite direction, the locking dogs 64 become unlatched so that an upward pull on the body 50 retracts them. An annular seal 69 is preferably employed also. A third pressure conduit 70 may be provided in the head of the lock-down body 50 (FIGURE 11) in order to obtain the tubing annulus well pressure.

Since in this well installation a pair of tubing strings 22 and 26 are employed, the production control unit or wellhead assembly 49 is provided with two flexible flow lines 43 and 44 which are adapted to lay on the ocean floor after the production control unit 49 has been lowered in the casing and tubing suspension body 11 and locked therein, as shown in FIGURE 6. The production control unit 49 contains the necessary piping, valves, chokes, and other equipment normally connected together, mounted on the top of a well and known as a Christmas tree together with the necessary hydraulic or electrical systems including pumps, reservoirs, tanks, motors, etc., to operate the valves at the head of the well from a remote location. A typical example of a suitable production control unit 49 for use at an offshore well location is shown and described in copending patent application Serial No. 834,096, filed August 17, 1959.

With the production control unit 49 seated and locked in place on the casinghead or casing and tubing suspension body 11, the running head 30 is disconnected from the top of the production control unit or wellhead assembly 49, or from its lubricator or wellhead closure device 45, and the running string 17 is then pulled upwardly to the surface, with the production control unit 49 left on the ocean floor (FIGURE 7). A typical lubricator or wellhead closure of this type is shown and described in copending patent application, Serial No. 830,587, filed August 30, 1959, now abandoned.

One suitable type of running tool for use in carrying out the method of the present invention is shown in FIGURE 12 as comprising a tubular housing 71, adapted to be secured to the lower end of a pipe string 17, and having slidably mounted therein a piston member 72 being normally urged downwardly by a compression spring 73. Extending downwardly from the piston 72 and axially movable therewith are a series of spring-loaded collet fingers 74 having latching surfaces 75 at their lower ends. The bore 76 through the housing 71 is enlarged as at 77, allowing the lower ends of the collet fingers 74 to be forced thereinto when the fishing head 25a is pulled past the latching surfaces 75., This action is only possible when the piston 72 has been raised in the housing 71 to raise the latching surfaces 75 of the collet'fingers- 74 off their seating shoulder 78.

The tool may engage a fishing head 25a by mechanicaL 1y forcing the tool downwardly on the head 25a. This action causes the piston and collet fingers to be pushed upwardly against the action of the spring 73 until the collet fingers are able to bend out into the recess 77 in the housing. They immediately snap back around the lower side of the fishing head 25a to hold it in the housing when seated on shoulder 78. The tool 30 is released from -the fishing neck by dropping a ball ordart 80 through the pipe string 17. The ball seat itself in and closes the bore 81 of the piston causing pressure fluid to be forced through lateral passages 82,- against shoulder 83, to force 7 the piston upwardly. The collet fingers are now free to move out into the recess 77 when an upward force is applied to the pipe tring 17.

1 This application is a continuat'ion-in-part of copending patent application, Serial No. 830,624, filed July 30, 1959, now Patent No. 3,062,288, issued on November 6 1962.

I claim as my invention:

1. In oil and gas well completion operations carried out from an operational base positioned above the surface of water, with a marine conductor pipe string extending from said base and connected to an underwater well casinghead, the method of installing dual tubing string in a well casing depending from an underwater well casinghead and mounting a wellhead assembly thereon, said method comprising closing said well casing to formation fluids under pressure, running dual strings of tubing simultaneously from said base above water down through said marine conductor pipe and casinghead and into said casing. attaching a stop member and a running string to the tops of said tubing strings, landing in said casinghead said stop member with said tubing strings depending therefrom and withdrawing said running tring, disconnecting from said casinghead said marine conductor pipe and withdrawing it to the above-water base, lowering a tool 'on a running string and guiding it within said casinghead to engage said tubing strings, withdrawing the upper ends of said'tubing strings to a point above the surface of the water with the lower ends ofthe tubing strings remaining in the well, attaching a wellhead assembly to the top of said tubing strings, and lowering the upper portion of said tubing strings back into said well casing with the wellhead assembly, and closing the upper end of said casinghead with said lowered wellhead assembly.

2. In oil and gas well completion operations carried out from an operational base positioned above the surface of water, with a marine conductor pipe string extending from said base to an underwater well casinghead provided with blow-out preventer means connected to said casinghead for emergency control of the well, the method of installing dual tubing strings in a well casing depending from an underwater Well casinghead and mounting a wellstring and guiding it within said casinghead to engage said tubing strings, withdrawing the upper ends of said tubing strings to a point above the surface of the water, with the lower ends of the tubing strings remaining in the well, attaching a wellhead assembly to the top of said tubing strings, lowering said upper portion of said tubing string back into said well casing with the wellhead assembly to close said casinghead, and setting the dual packer within the well casing.

3. In oil and gas well completion operations carried out from an operational base positioned above the surface of water, with a marine conductor pipe string extending from said base to an-underwater well casinghead provided with blow-out preventer means connected to said marine conductor pipe string and said casinghead for emergency control of the well, the method of installing dual tubing strings in a well casing depending from an underwater well casinghead and mounting a wellhead assembly thereon, said method comprising closing said well casing to formation fluids under pressure by inserting reopenable casing packer means through said marine conductor pipe and casinghead and running it through said well casing to a level above a formation to be produced at which level said casing packer means are set in fluidtightengagement with the inner wall of said casing, run- 'ing dual strings of tubing simultaneously from said base above water down through said marine conductorand casinghead and into said casing, attaching a tubing hanger and tubing adapter and a running string to the tops of said tubing strings, seating in said casinghead said tubing hanger with said tubing strings depending therefrom and withdrawing said running string, disconnecting from said casinghead said blow-out preventer means and withdraw ing it to the above-water base with said marine conductor, lowering a tool on a running string and guiding it within said casinghead to engage said tubing adapter, withdrawing said tubing adapter and connected hanger means and the upper ends of dual tubing strings to a point above the surface of the water with the lower ends of the tubing strings remaining in the well, removing said tubing adapter from said tubing hanger means, attaching a wellhead assembly to said tubing hanger in register with said dual tubing strings, lowering said dual tubing strings back into said well casing with the wellhead assembly, and closing the upper end of said casinghead with said lowered wellhead assembly.

4. Apparatus for installing dual tubing strings in an offshore well having an underwater well casinghead wherein the operations are carried out from an operational base above the surface of the water, said apparatus comprising a well casinghead positioned below the surface of water with a casing extending therefrom into the ocean floor, a marine conductor connected to the top of said casinghead in a fiuidtight manner and extending upwardly therefrom to a point above the surface of the water, dual tubing strings within said casinghead and casing, and stop means secured on the outside of said tubing string at the upper end thereof, said stop means adapted to seat on said casinghead, tubing adapter means removably attached to said stop means, and fishing head meansafiixedto the upper end of said tubing adaptor means.

5. Apparatus for installing dual tubing strings in an offshore well having an underwater well casinghead Wherein the operations are carried out from an operational base above the surface of the water, said apparatus comprising a well casinghead positioned below the surface of water with a casing extending therefrom into the ocean floor, a marine conductor connected to the top of said casinghead in a fluidtight manner and extending upwardly therefrom to a point above the surface of the water, dual tubing strings within said casinghead and easing, stop means secured on the outside of said tubing strings at the upper end thereof, said stop means adapted to seat on said casinghead, tubing adapter means removably attached to said stop means, and fishing head means afi'ixed to the upper end of said tubing adaptor means, and casing closure packer means afiixed to said dual tubing strings near the lower ends thereof.

6. The apparatus of claim 4 including casing closure means positioned in said well casing above a production zone and adapted to receive one of said tubing strings therein in a bore thcrethrough.

7. The apparatus of claim 6 wherein the lower ends of the dual tubing strings are connected together with a common tubing section extending downwardly therefrom and in communication with the bore through said casing closure means.

8. The apparatus of claim 4 including closure means having removable plug means the-rein and being positioned 1 3071'188 in said well casing above a production zone of said well.

References Cited by the Examiner UNITED STATES PATENTS CHARLES E. OCONNELL, Primary Examiner. 

1. IN OIL AND GAS WELL COMPLETION OPERATIONS CARRIED OUT FROM AN OPERATIONAL BASE POSITIONED ABOVE THE SURFACE OF WATER, WITH A MARINE CONDUCTOR PIPE STRING EXTENDING FROM SAID BASE AND CONNECTED TO AN UNDERWATER WELL CASINGHEAD, THE METHOD OF INSTALLING DUAL TUBING STRINGS IN A WELL CASING DEPENDING FROM AN UNDERWATER WELL CASING HEAD AND MOUNTING A WELLHEAD ASSEMBLY THEREON, SAID METHOD COMPRISING CLOSING SAID WELL CASING TO FORMATION FLUIDS UNDER PRESSURE, RUNNING DUAL STRINGS OF TUBING SIMULTANEOUSLY FROM SAID BASE ABOVE WATER DOWN THROUGH SAID MARINE CONDUCTOR PIPE AND CASING HEAD AND INTO SAID CASING, ATTACHING A STOP MEMBER AND A RUNNING STRING TO THE TOPS OF SAID TUBING STRINGS, LANDING IN SAID CASINGHEAD SAID STOP MEMBER WITH SAID TUBING STRING DEPENDING THEREFROM AND WITHDRAWING SAID RUNNING STRING, DISCONNECTING FROM SAID CASING HEAD SAID MARING CONDUCTOR PIPE AND WITHDRAWING IT TO THE ABOVE-WATER BASE, LOWERING A TOOL ON A RUNNING STRING AND GUIDING IT WITHIN SAID CASINGHEAD TO ENGAGE SAID TUBING STRINGS, WITHDRAWING THE UPPER ENDS OF SAID TUBING STRINGS TO A POINT ABOVE THE SURFACE OF THE WATER WITH THE LOWER ENDS OF THE TUBING STRING REMAINING IN THE WELL, ATTACHING A WELLHEAD ASSEMBLY TO THE TOP OF SAID TUBING STRINGS, AND LOWERING THE UPPER TO THE TOP OF SAID TUBING STRINGS BACK INTO SAID WELL CASING WITH THE WELLHEAD ASSEMBLY, AND CLOSING THE UPPER END OF SAID CASINGHEAD WITH SAID LOWERED WELLHEAD ASSEMBLY. 